To infect t cells, m-tropic human immunodeficiency virus-1 (hiv-1) strains bind to the cell surface protein ccr5, which is normally a receptor for various immunity-related factors. about 10 percent of scandinavians are heterozygous for a ccr5 allele with a 32-base-pair deletion that introduces a premature stop codon, thereby creating a protein that binds neither factors nor virus. heterozygous individuals exhibit some resistance to m-tropic hiv-1 infection, and homozygous individuals are very resistant to infection. in the case of hiv-1, this mutation has proven to be

A24-year-old g4p2 woman at 34 weeks gestation complains of a cough and whitish sputum for the last three days. she reports that everyone in the family has been sick. she reports a high fever last night up to 102°f (38.9°c). she denies chest pain. she has a history of asthma with no previous intubations. she uses an albuterol inhaler, although she has not used it this week. vital signs are: temperature 98.6°f (37°c); respiratory rate 16/minute; pulse 94 beats/minute; blood pressure 114/78; peak expiratory flow rate 430 l/min (baseline documented in the outpatient chart = 425 l/min). on physical examination, pharyngeal mucosa is erythematous and injected. lungs are clear to auscultation. white blood cell count 8,700 mcl; arterial blood gases on room air (normal ranges in parentheses): ph 7.44 (7.36–7.44); po2 103 mm hg (> 100); pco2 26 mm hg (28–32); hco3 19 mm hg (22–26). chest x-ray is normal. what is the correct interpretation of this arterial blood gas?